Portable power bank



FIG. 1 is a top right perspective view of a portable power bank showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a right front perspective view thereof; and,

FIG. 9 is a left rear perspective view thereof. 

CLAIM The ornamental design for a portable power bank, as shown and described. 